Vinyl chloride polymers plasticized with alkoxyethyl esters of (1&#39;, 2&#39;-dicarboxyethyl) octadecenoic acid



Patented Sept. 25, 1951 VINYL CHLORIDE POLYMERS PLASTICIZED WITHALKOXYETHYL ESTERS OF (1',2'- DICARBOXYETHYL) UNDIFCYLENIC ACID JoachimDazzi, Dayton, Ohio, assignor to Moncanto Chemical Company, St. Louis,Mo., a corporation of Delaware No Drawing. Application March 25 1950,Serial No. 151,996

6 Claims. (01. 2603l .8)

This invention relates to compositions comprising polymers of vinylhalides and relates more particularly to compositions comprising vinylchloride polymers plasticized with alkoxyethyl esters of(1',2-dicarboxyethyl)undecylenic acid.

A wide variety of plasticizers has been employed for the purpose ofimproving the physical properties of vinyl chloride polymers. Particularattention has been given to the improvement of flexibility and heat andlight stability of such plasticized compositions. In many instances theimprovement in flexibility has been obtainable only by sacrificing otherdesirable properties of an ideal polyvinyl chloride composition, such aslow volatility, color and heat stability, water absorption, etc.

Now I have found that very good flexibility, without sacrifice oftemperature stability and low volatility, is imparted to vinylchloridepolymers when there are employed with the polymers certainalkoxyethyl esters of(1',2'-dicarboxyethyl) undecylenic acid. Esters ofthis type are disclosed in the Clocker patent, U. S. No. 2,188,888.Briefly, they are obtainable by the addition reaction of maleicanhydride with undecylenic acid or its alkoxyethyl esters. Whileisomeric products are possible, and the position at which the anhydrideresidue is attached to the undecylenic compound is not known, thereaction of undecylenic acid or an alkoxyethyl undecylenate with maleicanhydride proceeds probably according to the scheme;CHi=CHCHz(CH:)CHzCOOC;H|OR CHC= wherein R is a member of the groupconsisting of hydrogen and alkyl radicals of from 1 to 6 carbon atoms.

the structure:

wherein R and R are alkyl groups of from 1 to 6 carbon atoms. Mixedalkoiqalkyl esters are thus obtainable.

Because of uncertainty concerning the position at which the maleicresidue is attached to the undecylenic group, the present esters will behereinafter referred to without stipulating the position of. the(l',2'-dicarboxyethyl) group.

I have found that in order to obtain stable, light-colored adductscertain reaction conditions must be adhered to carefully. For example,while the addition of maleic anhydride to undecylenic acid takes placeunder varying reaction conditions, useful plasticizers for the presentpurpose are best prepared by conducting the reaction for comparativelyshort periods of time, say, from 1 hour to 8 hours, at relatively lowtemperatures, i. e., at temperatures not exceeding the decompositionpoint of the initial reactants. I have found also that great care shouldbe used in isolating the desired products. After the esterification Ipreferably fractionate the crude reaction mixture under a very lowvacuum, i. e., at vacuums of 1 mm. of mercury or less. Fractionation atsuch low pressures minimizes the formation of dark-colored impuritieswhose presence in the finished product leads to poor plasticizingability. Dark-colored impurities are also avoided by preparing thetris(alkoxyethyl) (1',2-dicarboxyethyl) undecylenates according to theprocedure described in my copending application, Se-

rial No. 144,393, filed February 15, 1950.

The tris(alkoxyethyl) (1',2'-dicarboxyethyl)- undecylenates are valuableplasticizers for polyvinyl chloride and copolymers of at least 70 percent by weight of vinyl chloride and up to per cent by weight of anunsaturated monomer copolymerized therewith, for example vinyl acetate,vinylidene chloride, etc. Adducts of acyclic olefinic acids andlong-chained unsaturated acids have been hitherto generally suggestedfor use as softening agents. I have now found, however, that thetris(alkoxyethyl) (1',2-dicarboalkoxy) undecylenates in which the alkoxyradical has from 1 to 6 carbon atoms'are of outstanding value asplasticizers, these esters serving not only to soften vinyl chloridepolymers, but also to impart simultaneously a high degree of lowtemperature flexibility, very good temperature stability and greatmechanical strength to these polymers. While many of the estersdescribed in the prior art are incompatible with polymers and copolymersof vinyl chloride, and do not give continuous, homogeneous compositions,the present alkoxyethyl esters are compatible with vinyl chloridepolymers and show no exudation of plasticizer even at plastizer contentof up to 50 per cent. Although the quantity of plasticizer will dependupon the particular polymer to be plasits molecular weight, it isgenerally found that compositions having from 5 per cent to 50 per centby weight of plasticizer will, in most cases, be satisfactory forgeneral utility. The good flexibility of the plasticized composi tionsincreases with increasing plasticizer concentration.

In evaluating plasticizer emciency use is made of the followingempirical testing procedures:

Compatibility.-Visual inspection of the plasticized composition isemployed, incompatibility of the plasticizer with the polymer beingdemonstrated by cloudiness and exudation of the plasticizer.

H ardness.--A standard instrument made by the Shore Instrument Companyis used for this determination and expresses the hardness in units from1 to 100. The hardness of a composition is judged by its resistance tothe penetration of a standard needle applied to the composition under astandard load for a standard length of time.

Low temperature flexibility.Low temperature flexibility is one of themost important properties of elastomeric vinyl compositions. While manyplasticizers will produce flexible compositions at room temperature theflexibility of these compositions at low temperatures may varyconsiderably, i. e., plasticized polyvinyl chloride compoticized andupon sitions that are flexible at room temperature often become verybrittle and useless at low temperatures. Low temperature flexibilitytests herein employed are according to the Clash-Berg method. Thismethod determines the torsional flexibility of a plastic at Thetemperature at which the vinyl composition exhibits an arbitrarilyestablished minimum flexibility is defined as the low temperatureflexibility of the composition. This value may also be defined as thelower temperature limit of the plasticized compositions usefulness as anelastomer.

Volatility.--Just as a decrease in low temperature often results indecreased flexibility of a plasticized polymer composition so does adecrease in plasticizer concentration when caused by volatilization ofthe plasticizer. Hence, plasticizers which are readily volatilized fromthe plasticized composition as a result of aging or heating areineflicient because upon volatilization the plasticized compositionsbecome stiff and hard. The test for plasticizer volatility hereinemployed is that described by the American Society for Testing Materialsunder the designation D744-44T.

Water resistance-The amount of water absorption and the amount ofleaching that takes place when the plasticized composition is immersedin distilled water for 24 hours is'determined.

The invention is further illustrated, but not limited, by the followingexample:

Example 60 parts of polyvinyl chloride and 40 parts by weight of thetris(ethoxyethy1) ester of (1',2'- dicarboxyethyl) undecylenic acid aremixed on a rolling mill to ahomogeneous blend. Durin the milling therewas observed substantially no fuming and discoloration. A molded sheetof the mixture was clear and transparent and substantially colorless.Testing of the molded sheet for low temperature flexibility, accordingto the testing procedure described above, gave a value of minus 44 C.which value denotes extremeLv various temperatures. 1

good low temperature properties. Tests on the volatility characteristicsof the p composition gave a value of 2.99 per cent which shows very goodretention of plasticizer and indicated good temperature characteristicsof the composition. The plasticized material had a hardness of 71 beforethe volatility test and a hardness of 73 after the volatility test. Whensubjected to heat at a temperature of 325 F. for a! period of minutesthe clarity and color of the molded product was substantially unchanged.Tests of the water resistance properties of the plasticized materialemploying the test procedure described above showed a solidsloss of only0.39 per cent and an 0.72 per cent water absorption value.

Instead of the esters employed in the example above, othertris(alkoxyethyl) esters of (1',2'- dicarboxyethyl) undecylenic acidhaving from 1 to 6 carbon atoms in the alkoxy group give similarlyvaluable plasticized polyvinyl chloride compositions. Thus, by employingparts by weight of tris(methoxyethyl), tris(isobutoxyethyl), tris-(n-hexyloxyethyl) or tris(propoxyethyl) ester of(l',2'-dicarboxyethyl)undecylenic acid with parts by weight of polyvinylchloride or with 60 parts by weight of a vinyl chloridevinyl acetatecopolymer known to the trade as Vinylite, there are obtained clear,colorless compositions of very good flexibility and stability.

While the above example shows only a composition in which the ratio ofplasticizer to polymer content is 40:60, this ratio being employed inorder to get comparable efiiciencies, the content of ester to polyvinylchloride may be widely varied, depending upon the properties desired inthe final product. For many purposes a plasticizer content of, say, fromonly 10 per cent to 20 per cent is preferred. The present esters arecompatible with polyvinyl chloride over a wide range of concentrations,up to 30 per cent of esters based on the total weight of the plasticizedcomposition yielding desirable products.

Although the invention has been described particularly with reference tothe use of the present tris(alkoxyethyl) esters of(1',2'-dicarboxyethyl) undecylenic acid as plasticizers for polyvinylchloride, these esters are advantageously employed also as plasticizersfor copolymers of vinyl chloride, for example, the copolymers of vinylchloride with vinyl acetate, vinylidene chloride, methyl methacrylate,acrylonitrile, etc. Preferably, such copolymers have a high vinylchloride content, i. e., a vinyl chloride content of at least '70 percent by weight of vinyl chloride and up to 30 per cent by weight of thecopolymerizable monomer.

The plasticized polyvinyl halide compositions of the present inventionhave good thermal stability; however, for many purposes it may beadvantageous to use known stabilizers in the plasticized compositions.Inasmuch as the present esters are substantially unreactive with thecommercially available heat and light stabilizers which are commonlyemployed with polyvinyl chloride or copolymers thereof, the presence ofsuch materials in the plasticized materials does not impair the valuableproperties of the present esters. The present esters are of generalutility in softening vinyl chloride polymers. They may be used as theonly plasticizing component in a compounded vinyl chloride polymer orthey may be used in conjunction with other plasticizers.

What I claim is:

1. A resinous composition comprising a vinyl r 5 chloride polymerplasticized with a tris(alkoxyethyl) ester of(1,2'-dicarboxyethyl)undecylenic acid in which the alkoxy group has from1 to 6 carbon atoms.

2. A resinous composition comprising polyvinyl chloride plasticized witha. tris(a1koxyethyl) ester of (1,2'-dicarboxyethy1)undecylenic acid inwhich the alkoxy group has from 1 to 6 carbon atoms.

3. A resinous composition comprising polyvinyl chloride plasticized witha tris(alkoxyethyl) ester of (1',2'-dicarboxyethyl) undecylenic acid inwhich the alkoxy group has from 1 to 6 carbon atoms, said ester beingfrom 5 to 50 per cent of the weight of the composition.

4. A resinous composition comprising a copolymer of at least 70 per centby weight of vinyl chloride and up to 30 per cent by weight of anunsaturated monomer copolymerizable therewith, said copolymer beingplasticized with a tris- (alkoxyethyl) ester of (1',2'-dicarboxyethyl)undecylenic acid in which the alkoxy group has from 1 to 6 carbon atoms.

5. A resinous composition comprising a copolymer of at least 70 per centby weight of vinyl chloride and up to 30 per cent by weight of anunsaturated monomer copolymerizable therewith, said copolymer beingplasticized with a tris- (alkoxyethyl) ester of(1',2-dicarboxyethyl)undecyienic acid in which the alkoxy group has from1 to 6 carbon atoms, and said ester being from 5 to 50 per cent of theweight of the composition.

6. A resinous composition comprising polyvinyl chloride plasticized withthetris(ethoxyethyl) ester of (1,2'-dicarboxyethyl)undecylenic acid,said ester being from 5 to 50 per cent of the weight of the composition.

JOACHIM DAZZI.

REFERENCES CITED UNITED STATES PATENTS Name Date Sarbach Oct. 25, 1944Number

1. A RESINOUS COMPOSITION COMPRISING A VINYL CHLORIDE POLYMERPLASTICIZED WITH A TRIS(ALKOXYETHYL) ESTER OF (1'',2''-DICARBOXYETHYL)UNDECYLENIC ACID IN WHICH THE ALKOXY GROUP HAS FROM 1 TO 6 CARBON ATOMS.